Abstract

ANDRADE-GAMBOA, Julio José  and  DONATI, Edgardo R.. Induced misinterpretations: the case of the sulfur phase diagram. Educ. quím [online]. 2022, vol.33, n.1, pp.150-161.  Epub Nov 11, 2022. ISSN 0187-893X.  https://doi.org/10.22201/fq.18708404e.2022.1.79821.

Pure substance phase diagrams, as pressure versus temperature graphs, are usually introduced in first university courses in chemistry. In general, off-scale schematic diagrams are used to cover a full range of pressures and temperatures. In them, to highlight certain behaviors of the substances, some details are accentuated or exaggerated, and this implies a greater risk of inducing comparative misconceptions than using scale diagrams. Taking in account that graphic representations are important tools in the teaching of concepts and in the recognition of physical and chemical phenomenologies, to avoid conceptual errors, schematic diagrams and their inherent distortions should be carefully discussed with students. In the present work, the sulfur phase diagram is taken as an example, because, both in textbooks and in scientific articles, it is often shown with some qualitative errors.

Keywords : One-component phase diagrams; Phase equilibria; Clapeyron equation; Sulfur; Graphic errors.